Calibration of the physiological equivalent temperature index for three different climatic regions

Abstract

In human biometeorology, the integration of several microclimatic variables as a combined index facilitates the understanding of how users perceive thermal environments. Indices, such as the physiological equivalent temperature (PET) index, translate the combined effects of meteorological variables on humans in terms of thermal stress or comfort and serve as important aids to climate-responsive urban and regional planning as well as heat stress and thermal comfort analyses. However, there is a need for adjusting proposed comfort/stress ranges of a given index when using it in different climatic contexts. The purpose of this study is to present a preliminary calibration procedure for the PET index for three different climatic regions: Curitiba, Brazil, a subtropical location; Rio de Janeiro, Brazil, a tropical city; and Glasgow, UK, a high-latitude location. Field studies have been carried out by the authors according to a similar protocol and using similar equipment, yielding actual thermal sensation votes and microclimate data, post-processed as PET data. The calibration procedure uses exclusively thermal sensation data as reported by pedestrians during outdoor comfort campaigns and concurrent microclimatic data recorded during the interviews. PET comfort/stress classes differ among the three locations and, in general, are less restrictive as in the original ranges proposed by the index developers.

Subjective Human Perception of Open Urban Spaces in the Brazilian Subtropical Climate: A First Approach

“…For studies in which the PET index in subtropical climates was used, different patterns of definition of the thermal comfort zone for different locations were observed, even when these places are in the same climatic zone . The same behavior can be observed for the SET and PMV indices as well [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35].…”

“…In turn, Krüger, Rossi, and Drach [24] found an average of 25 • C as defining the comfort range for Curitiba through the use of a binary method, according to the values of the assessed index. These authors performed a preliminary calibration of the PET for three different climatic regions.…”

“…Krüger, Rossi, and Drach [24] described a preliminary procedure for the calibration of the PET for three different climatic regions: Curitiba, Brazil (subtropical climate), Rio de Janeiro, Brazil (tropical climate), and Glasgow, United Kingdom (high-latitude climate).…”

“…Several studies have detected differences in outdoor thermal comfort across different climatic regions [24][25][26][27] and have pointed to the need for additional fieldwork research on subjective human perception in different climatic regions [20], given that most of those surveys currently available have mainly been conducted in areas with temperate or tropical climates.…”

Assessing the Effects of Urban Morphology Parameters on Microclimate in Singapore to Control the Urban Heat Island Effect

“…In addition, due to the differences registered in the thermal perception of different populations, it is necessity to perform study aimed at evaluating the microclimate of a specific city or site [21,22]. According to previous studies, the main microclimate parameters affecting any open space include land cover, site geometry, and spatial location (e.g., proximity to parks or water bodies).…”